<?php

/**
 * @file
 * Functions to aid in the creation of sortable tables.
 *
 * All tables created with a call to theme('table') have the option of having
 * column headers that the user can click on to sort the table by that column.
 */


/**
 * Query extender class for tablesort queries.
 */
class TableSort extends SelectQueryExtender {

	/**
	 * The array of fields that can be sorted by.
	 *
	 * @var array
	 */
	protected $header = array();

	public function __construct(SelectQueryInterface $query, DatabaseConnection $connection) {
		parent::__construct($query, $connection);

		// Add convenience tag to mark that this is an extended query. We have to
		// do this in the constructor to ensure that it is set before preExecute()
		// gets called.
		$this->addTag('tablesort');
	}

	/**
	 * Order the query based on a header array.
	 *
	 * @see theme_table()
	 * @param $header
	 *   Table header array.
	 * @return SelectQueryInterface
	 *   The called object.
	 */
	public function orderByHeader(Array $header) {
		$this->header = $header;
		$ts = $this->init();
		if (!empty($ts['sql'])) {
			// Based on code from db_escape_table(), but this can also contain a dot.
			$field = preg_replace('/[^A-Za-z0-9_.]+/', '', $ts['sql']);

			// Sort order can only be ASC or DESC.
			$sort = drupal_strtoupper($ts['sort']);
			$sort = in_array($sort, array('ASC', 'DESC')) ? $sort : '';
			$this->orderBy($field, $sort);
		}
		return $this;
	}

	/**
	 * Initialize the table sort context.
	 */
	protected function init() {
		$ts = $this->order();
		$ts['sort'] = $this->getSort();
		$ts['query'] = $this->getQueryParameters();
		return $ts;
	}

	/**
	 * Determine the current sort direction.
	 *
	 * @param $headers
	 *   An array of column headers in the format described in theme_table().
	 * @return
	 *   The current sort direction ("asc" or "desc").
	 */
	protected function getSort() {
		return tablesort_get_sort($this->header);
	}

	/**
	 * Compose a URL query parameter array to append to table sorting requests.
	 *
	 * @return
	 *   A URL query parameter array that consists of all components of the current
	 *   page request except for those pertaining to table sorting.
	 *
	 * @see tablesort_get_query_parameters()
	 */
	protected function getQueryParameters() {
		return tablesort_get_query_parameters();
	}

	/**
	 * Determine the current sort criterion.
	 *
	 * @param $headers
	 *   An array of column headers in the format described in theme_table().
	 * @return
	 *   An associative array describing the criterion, containing the keys:
	 *   - "name": The localized title of the table column.
	 *   - "sql": The name of the database field to sort on.
	 */
	protected function order() {
		return tablesort_get_order($this->header);
	}
}

/**
 * Initialize the table sort context.
 */
function tablesort_init($header) {
	$ts = tablesort_get_order($header);
	$ts['sort'] = tablesort_get_sort($header);
	$ts['query'] = tablesort_get_query_parameters();
	return $ts;
}

/**
 * Format a column header.
 *
 * If the cell in question is the column header for the current sort criterion,
 * it gets special formatting. All possible sort criteria become links.
 *
 * @param $cell
 *   The cell to format.
 * @param $header
 *   An array of column headers in the format described in theme_table().
 * @param $ts
 *   The current table sort context as returned from tablesort_init().
 * @return
 *   A properly formatted cell, ready for _theme_table_cell().
 */
function tablesort_header($cell, $header, $ts) {
	// Special formatting for the currently sorted column header.
	if (is_array($cell) && isset($cell['field'])) {
		$title = t('sort by @s', array('@s' => $cell['data']));
		if ($cell['data'] == $ts['name']) {
			$ts['sort'] = (($ts['sort'] == 'asc') ? 'desc' : 'asc');
			$cell['class'][] = 'active';
			$image = theme('tablesort_indicator', array('style' => $ts['sort']));
		}
		else {
			// If the user clicks a different header, we want to sort ascending initially.
			$ts['sort'] = 'asc';
			$image = '';
		}
		$cell['data'] = l($cell['data'] . $image, $_GET['q'], array('attributes' => array('title' => $title), 'query' => array_merge($ts['query'], array('sort' => $ts['sort'], 'order' => $cell['data'])), 'html' => TRUE));

		unset($cell['field'], $cell['sort']);
	}
	return $cell;
}

/**
 * Format a table cell.
 *
 * Adds a class attribute to all cells in the currently active column.
 *
 * @param $cell
 *   The cell to format.
 * @param $header
 *   An array of column headers in the format described in theme_table().
 * @param $ts
 *   The current table sort context as returned from tablesort_init().
 * @param $i
 *   The index of the cell's table column.
 * @return
 *   A properly formatted cell, ready for _theme_table_cell().
 */
function tablesort_cell($cell, $header, $ts, $i) {
	if (isset($header[$i]['data']) && $header[$i]['data'] == $ts['name'] && !empty($header[$i]['field'])) {
		if (is_array($cell)) {
			$cell['class'][] = 'active';
		}
		else {
			$cell = array('data' => $cell, 'class' => array('active'));
		}
	}
	return $cell;
}

/**
 * Compose a URL query parameter array for table sorting links.
 *
 * @return
 *   A URL query parameter array that consists of all components of the current
 *   page request except for those pertaining to table sorting.
 */
function tablesort_get_query_parameters() {
	return drupal_get_query_parameters($_GET, array('q', 'sort', 'order'));
}

/**
 * Determine the current sort criterion.
 *
 * @param $headers
 *   An array of column headers in the format described in theme_table().
 * @return
 *   An associative array describing the criterion, containing the keys:
 *   - "name": The localized title of the table column.
 *   - "sql": The name of the database field to sort on.
 */
function tablesort_get_order($headers) {
	$order = isset($_GET['order']) ? $_GET['order'] : '';
	foreach ($headers as $header) {
		if (is_array($header)) {
			if (isset($header['data']) && $order == $header['data']) {
				$default = $header;
				break;
			}

			if (empty($default) && isset($header['sort']) && ($header['sort'] == 'asc' || $header['sort'] == 'desc')) {
				$default = $header;
			}
		}
	}

	if (!isset($default)) {
		$default = reset($headers);
		if (!is_array($default)) {
			$default = array('data' => $default);
		}
	}

	$default += array('data' => NULL, 'field' => NULL);
	return array('name' => $default['data'], 'sql' => $default['field']);
}

/**
 * Determine the current sort direction.
 *
 * @param $headers
 *   An array of column headers in the format described in theme_table().
 * @return
 *   The current sort direction ("asc" or "desc").
 */
function tablesort_get_sort($headers) {
	if (isset($_GET['sort'])) {
		return (strtolower($_GET['sort']) == 'desc') ? 'desc' : 'asc';
	}
	// The user has not specified a sort. Use the default for the currently sorted
	// header if specified; otherwise use "asc".
	else {
		// Find out which header is currently being sorted.
		$ts = tablesort_get_order($headers);
		foreach ($headers as $header) {
			if (is_array($header) && isset($header['data']) && $header['data'] == $ts['name'] && isset($header['sort'])) {
				return $header['sort'];
			}
		}
	}
	return 'asc';
}
